Process for forming films and filaments



Aug. 25, 1959 w. STEUBER Re. 24,691v

PROCESS FOR FORMI FILMS AND FILAMENTS DIRECTLY FROM P MER I RMEDIATESOriginal Filed Feb. 1955 INVENTOR WALTER STEUBER BY 7% I ATTORNEY UnitedStates Patent fi ice Re. 24,691 Reissuetl Aug. 25, 1959 PROCESS FORFORMING FILMS AND FILAMENTS DIRECTLY FROM POLYMER INTERMEDIATES WalterSteuber, Springfield, Pa., assignor to E. I. du Pont de Nemours andCompany, Wilmington, Del., a corporation of Delaware Original No.2,813,7 75, dated November 19, 1957, Serial No. 489,583, February 21,1955. Application for reissue November 25, 1958, Serial No. 776,666

20 Claims. (Cl. 18-54) Matter enclosed in heavy brackets appears in theoriginal patent but forms no part of this reissue specifi cation; matterprinted in italics indicates the additions made by reissue.

This invention relates to a process. More particularly it concerns aprocess for forming a shaped body having a continuous cross section, bycombination of two liquid complementary reactive polymer intermediates,the said combination being accomplished by extruding one of the saidintermediates into the other.

It is an object of the present invention to provide -a process for theproduction of a shaped body of continuous cross section by combinationof two liquid complementary reactive polymer intermediates.

Another object is to provide a process for the production of an elasticshaped body of continuous cross section by combination of two liquidcomplementary reactive polymer intermediates.

These and other objects will become apparent in the course of thefollowing specification and claims.

In accordance with the present invention a process is provided whichcomprises forming a solid shaped structure of continuous cross sectionby combining at least two liquid complementary reactive polymerintermediates, one of which contains at least two active hydrogens morereactive than alcoholic hydrogen, whereas its complement contains atleast two reactive groups capable of reacting with alcohol at roomtemperature to form an ester, and at least one of the said complementaryreactive polymer intermediates being a multi-functional organicmacromolecule possessing recurring amide type linkages and having amolecular weight within the range of from about 400 to about 7000, andat least one of the other of the said complementary reactive polymerintermediates being a poly functional, essentially monomeric, organicmolecule, the proportionate molecular weights of macromolecularintermediate to the essentially monomeric molecular intermediate beingsuch that at least about 30% by Weight of the final shaped structure iscontributed by the macromolecular intermediate [while at least about byweight of the final shaped structure is contributed by the essentiallymonomeric molecular intermediate], the combination of the saidcomplementary intermediates being accomplished by extrusion through anorifice of one said complementary polymer intermediate into the other.

The liquid complementary reactive polymer intermediates correspond tothe formulae:

wherein n is a small integer greater than 1, X is hydrogen more activethan alcoholic hydrogen, Y is a group capable of reacting with alcoholat room temperature to form an ester, R and R are members of the classconsisting of the radical of a polyfunctional essentially monomericorganic polymer intermediate and the radical of a polyfunctionalmacromolecular polymer intermediate containing recurring amide-typelinkages and having a molecular weight range of from about 400 to about7000. The complementary reactive polymer intermediates are so chosenthat at least 30% and preferably 60% of the weight of the final shapedarticle is contributed by the polyfunctional organic macromolecule{whereas at least 10% of the weight of the final shaped article iscontributed by the polyfunctional, organic, essentially monomericmolecule].

'By the expression a shaped body of continuous cross section is meant asolid structure in the nature of a filament or film whose cross sectionis uniform and unbroken as opposed to structures which have soft orhollow centers. The terms monomeric and essentially monomeric are usedinterchangeably to signify a monomer or a polymer having a low degree ofpolymerization, i.e., dimer, trimer, etc. The term polyfunctionalindicates the presence upon the molecule of at least two reactive groupscapable of reaction with a complementary functionally substitutedmolecule to form a polymer under conditions of the present invention.The expression polymer intermediate denotes a molecule polyfunctionallysubstituted and capable of reacting with a complementarypolyfunctionally substituted molecule to form a polymer under reactionconditions of the present invention. By the expression amide-typelinkages is meant that the molecule contains between recurring units,linkages represented by the formula it 1i wherein X II A is a member ofthe class consisting of o s II N g and 0 g H o and R is hydrogen, loweralkyl, and lower alkylene when the diamine has a ring structure.

Figure 2 is a diagramamtic sketch of the typical spinning set-up of thepresent invention.

Figure l is an illustration of a cross-sectional element of a filamentprepared in accordance with the present invention.

In Figure 2 one of the reactive intermediates is supplied through thesupply tube 2 and extruded through the orifice 3 into the othercomplementary reactive polymer intermediate 1. The filament 4 which isformed by the reaction of the two intermediates is then led around therollers 5 and 6 to be wound in the conventional manner.

The following examples are cited to illustrate the invention. They arenot intended to limit it in any manner. Among the physical propertiesreported for the products in the examples, polymer melt temperature isthe minimum temperature at which a sample of the polymer leaves a wet,molten trail as it is stroked with moderate pressure across a smoothsurface of a heated brass block. Fiber stick temperature is thetemperature at which the fiber will just stick to a heated brass blockwhen held against the surface of the block for 5 seconds with a 2.00grams weight. Zero strength temperature is the average temperature atwhich the two ends of the fiber break if heating is continued with the 3weight left on after the fiber stick temperature has been determined.Initial modulus is determined by measuring the initial slope of thestress strain curve. The .i sm q has particula alu n the .ptepara e 'ofai t-t sl s .1axiss hi a... Y this p op y st uct es a n l d d wh x it elsti reeqygeriesabove90% and stress decays below 20%. :Elastic recoveryis vthe percentage return to original length W .1 9. m nute after thetension has beensreleased .ir in-a sample which has elongated 50% .atthe rate of ,;1-00% per minute andlheld at 50% elongation for.onetninute. fStress decay is the percent lossjn stress in a yarn oneminute after it has been, elongated to 50% s il ratev .Q 7 m nute-EXAMPLE I A low mo ecula w is i poly m d e prepare y r 113-5 ste (.0 0mo o a aquenus solu ion son 5%.he am fltvl n diamin wi h 1-.5-0 ams 08mol) of azelaicacid a la ge polymer-tube. The eua ilfl ed f hed wit rogn, an h i on n ,melted at 245 .Wnter is removed for 20 hours at t at tepe a u e at atmo ph c p e u e a und vvacuum for V3 hoursuntil a tinalpressure of O. 2 mm. of mer-curyis obtained. A 95% yield ofcalibQXYl-free polymer with an average molecular weight of16.7.8isobtained.

ma r m l c lar me m. iat p em s d, is ex rude th ou h a n lehol spinn tinto a 2 C- .ba co p s n 2 hi wei h of -m thvl mip eny n is eya ate in asilicon oil Q- F u m-mi d w -.DOW lC r i-ns Corpof id nd, .M his Thfilaments obtained vare drawabletwotimestheir extruded length in hotair. They have a polymer melt temperature of about 200 C.

EXAMPLE II A polyamide with a molecular weight of 1500 is prepared byheating N,N'-diisobutylhexamethylenediamine with azelaic acid overnight.This liquid, macromolecular intermediate with ends is extruded through aone-hole spinners t into liquid ,hexamethylenediisocyanate (a monomericintermediate) at room temperature to produce a rubbery filament.

EXAMPLE HI The low molecular weight polyamide of the preceding exampleis mixed with 2 mols of triethylamine (an acid acceptor) for each mol ofpolymer. This mixture is extruded through a one-hole spinneret intoliquid sebacyl chloride at room temperature. A rubbery filamentisobtained.

' EXAMPLE IV A Ftrimer with hydroxyl ends isprepared by heating andstirring 3 mols of poly(tetrarnethylene oxide) glycol having a molecularweight of 1000 with 2 mols of 4- methyl-m-phenylenediisocyanate andcontinuing the heating for Shoursover a steam bath. This product isprovideflwifl reactive isocyanate. ends byreacting-it for one hour undersimilar. conditionswith 2 mols ofp ,p-methylenediphenylisocyanate :foreach mol of trimer. The P1 dUQI fromthe second reactionismixedwithsuflicient N,N-dimethylfonnamide to make a spin dope containing 7lids The sp d pe e u a 3 4. po per square inchthroughan 8 mil one=holespinneretinto aliquid ethylenediantlinebath. The filaments formed areremoved atfla rate of 56 feetperminute. They are thereaft rtransfe r dhmu ai om th tal lP to a se ond I011. w ic c lle s th fi m a a'r of 80.feetper minute. They are then wound up one bobbin immersed in water at67 feetper minute. The as-spun filaments are heat-set in ,water andboiled-0E to yield fi am nt w th. the ,i llowing p op rti nac ty= 19-1elcna tione319%, initial m du u =0l en s den e 45. st es deay;8.1%. a dnsil reco ery 8%. Thepolymer in hesefila e has n in eren v1scos-ity inhexamethylphosphoramide of 1.03, as com- EXAMPLE V A portion of the spindope of the preceding example .is extruded intoabath comprising 50%ethylene .diarnine and 50% triethylcnetetraminc. The filament obtainedisremoved from the bath at a rate of 44 feet per minute and is woundupat a r-ate of 57 feet perminute on abobbin immersed in water. Afterrelaxing in boiling-water, the as-spun filaments have the followingproperties: Tenacity=0;25 g.-p.-d., elogation:332%, initialmodulus =0.24g.p .d.,,,denier=l87, stress decay=15 percent, .and tensilerecovery='96%.

As will be apparent from the examples above, the polymer comprising thefinal shaped article may be of the linear, cross-linked or a combinationof-the two varieties. Furthermore, the polymeric product, regardless ofits variety of linkage, may be of a coupled type, i.e. only one of eachof two complementary intermediates is used in its production, orsegmented, i.e. a mixture of at least two 'homofunctional species of oneintermediate is reacted with one ormorespecies of complementaryhomofunctional intermediates. vIn the 'fonnation-of the segmentedproducts the speed of reaction between the-various complementaryintermediates is preferably substantially equal. It is preferablethatthespeed of reaction of the fastest reactingcomplementaryintermediates be close to the speed ofreaction oftheslowestreacting complementary intermediates in any particular system.

The invention is particularly useful inthe preparation of shapedarticles possessingelasticity. The degree of elasticity will varysomewhat the identity of the complementary polymer intermediates.

The effect of the macromolecularpolymer intermediates is particularlypronounced in-this regard. In general highly elastic products maybe:formed with macromolecularintermediates having a molecular weight in thelower endof the'range specified, i.e., around 400, provided the productiscross-linkedor segmented with units of polymer derived fromessentially monomeric polymer intermediates. Arnacromolecularintermediate of somewhat highenmolcular weight, around 800, ispreferable,

when the product formedi-s a linear coupled polymer.

The use of a macromolecular intermediate having ameltingpointnohigher-than about 50C. is particularlyadvantageousinimparting elasticity to'the final product.

The elastic properties of the structures obtained is varied to a lesserextentby the ssentially monomolecular intermediates. Thisappliesparticularly to the structures ing together toform a polymerwitha-polymer melt temperature above 200 C. in the fiber-forming -molecularweight'range. The higher the melting point of this segment, the closerthe molecular weight of the macromolecularintermediate can approachtherninimumyalue and still retain excellent elasticity. If the reactivemacromolecular intermediate is extruded into a liquid comp-rising onlyone complementary, essentially monomeric fast-reacting intermediate,then-it is preferred that this essentially. monomeric intermediatebecapable of reactionwithithe endgroups of the macromolecular intermediateto form a polymer which melts above 250 C. in the fiber-formingmolecular .weight range. The variation of elasticity caused by thecharacter. of the essentially monomolecular intermediate, as mentionedabove, is .much less pronounced When cross-linked structures areprepared. However, generally it is preferred that the final structurecon tain only a small number of cross-links per molecule. This can beaccomplished by using a relatively high molecular Weight macromolecularintermediate (one having a a molecular weight in the range of about 3000to about 5000) or by using at least two complementary essentiallymonomeric intermediates, one of which is difunctional and one of whichis multifunctional, the latter representing a small percentage of themixture.

The use of a macromolecular intermediate having a molecular Weight abovethe indicated minimum values has an advantage due to the fact that ahigh molecular weight fiber-forming polymer is obtained by combinationof a relatively small number of molecules. As a result, littleby-product is formed, particularly where polymerization proceeds bycondensation. This simplifies tllreadline formation and attendantpurification processes. Furthermore, high solids spinning dopes (i.e.the material extruded) can be used, which reduces solvent removal andrecovery problems. An important end result is the ready formation ofsolid structures, such as filaments and films, rather than collapsedtubular filaments or laminated films. For these reasons the use of atleast one macromolecular intermediate having a molecular Weight of about1000 to about 5000 is preferred.

The liquid complementary reactive polymer intermediates are combined inaccordance with the present invention, by extruding at least one suchintermediate through an orifice into its complement and the shapedarticle formed is led away from the orifice as it forms to a reel orother suitable conventional wet-processing collecting means. Generallyit is preferred to extrude the phase containing the macromolecularintermediate. For spinning fibers extrusion may be through aconventional wetspinning spinneret. A spinneret providing an orifice ofabout 3 to about mils is preferred although orifices of larger diametermay be employed. Furthermore, orifices of shapes other than round aresuitable. A slotted orifice may be used to produce films and ribbons.The shaped article may be Washed, stretched, lubricated or otherwiseafter-treated.

Preferably each complementary reactive inter-mediate is a liquid underthe conditions of the reaction or is dissolved in a liquid diluent.However, one of the said intermediates may be a finely divided soliddispersed in a liquid in which it is at least partially soluble. Whendiluents are employed it is preferred that the total concentration ofthe extruded intermediate be at least about 35% by weight of extrudedmaterial. Use of higher concentrations promotes compactness of thepolymeric structure and reduces the problems associated with handlinglarge volumes of solvents, particularly the organic solvents, which tendto be toxic, expensive, inflammable, etc. Satisfactory solid productscan be obtained by using lower concentrations for some sets ofcomplementary intermediates.

The speed at which the formed solid shaped products can be collectedwill depend upon the specific reactants and reaction conditions, such asthe diluents used and the concentration of the reactants in thesediluents. Much of the influence exerted by the diluents appears to liein their eifect upon the base strength of the intermediate reactantwhich is to act as a proton donor in the reaction. For example, theeffect is quite marked when water is used as a. diluent, but inertdiluents for diamines, such as benzene and dioxan, appear to exertlittle noticeable effect on the course of the reactions involved in thisprocess. Additional functions of the diluents are to control theviscosity of the phases and the interfacial tension between the extrudedphase and the bath. For example, it has been noted that the addition oflow percentages of N,N-dimethylformamide to viscous spin dopes permitsbetter penetration by the bath and results in higher tenacities.

Useful inert diluents for diamines include dioxan, benzene,tetrahydrofuran, and the like. Suitable inert materials for dilutingacid halides, such as acid chlorides and chloroformates, includebenzene, toluene, xylene, cyclohexane, trichloroethylene, chlorobenzene,nitrobenzene, heptane, isooctane, diethyl ether, ethyl acetate, methylamyl ketone, ethylene dichloride, carbon tetrachloride, chloroform, etc.It is essential that the diluents be materials which do not react asreadily'with either polymer-forming intermediate as does itscomplementary intermediate, and thus reduce the probability of polymerformation.

While it is sometimes desirable to add an acid acceptor to a systemwhich involves a reaction between a diacid halide and a coreactant, itis not necessary to do so. The particular advantage in using about anequivalent of alkali per equivalent of diamine in the bath is that itregenerates the diamine from any amine hydrohalide that forms, andminimizes the recovery of diamine from bath liquors. The process isordinarily operated at room temperature, although temperatures rangingfrom 10 C. to C. have been used successfully.

As previously defined, one of the complementary polymer intermediatescontains at least two active hydrogens more reactive than alcoholichydrogen, i.e. the hydrogen of an alkanol. Among end groups providingsuch a hydrogen may be mentioned SH, phenolic-OH, amino- NHR (in which Ris H or alkyl) and amidino. The other complementary polymer intermediatecontains at least two reactive groups capable of reacting with alcoholto form an ester. Among such groups may be mentioned the acid chloridegroup, the chloroformate group and the isocyanate group. The use ofcomplementary polymer intermediates which form a self-supportingpolymeric structure within 10 seconds after combination at roomtemperature is preferred. A large variety of suitable such combinationsis illustrated in copending U.S. application No. 226,066, filed May 12,1951, now Patent No. 2,708,617.

As previously disclosed the multifunctional organic macromolecularintermediate is a compound having a molecular weight within the range offrom about 400 to about 7000 and containing recurring amide-typelinkages. Suitable materials include polyamides, polyureas,polysulfonamides, polyurethanes combinations of these and the like. Thepolymer chains may be interrupted by oxygen or sulfur. They may hesubstituted with halogen or the like.

Polyurethanes suitable for use as macrointermediates can be prepared byreacting the bischloroformates of glycols, such as ethylene glycol,cyclohexanediol, or the polyether glycols, with a primary or secondarydiamine, such as hexamethylenediamine, 1,4-diaminocyclohexane,pphenylenediamine, and piperazine. For elastomers, these are preferablythe aliphatic diamines, such as ethylene diamine, propylene-diamine,butylenediamine, pentamethylenediamine, hexamethylenediamine, andN,N-diisobutylhexarnethylenediamine. As shown by the examples, this canalso be accomplished by reacting low molecular weight polyether glycols,such as the poly(alkylene oxide) glycols, with diisocyanates.

Polyureas may be obtained by (1) reacting diamines With phosgene, (2)reacting phosgene with a diamine to [form a biscarbamyl chloride, whichis reacted subsequently with another diamine: or more of the samediamine to form a polyure-a, or (3) by reacting a diamine with adiisocyanate. Any diamine, such as ethylenediamine, propylenediamine,butylenediamine, pentamethylenediamine, hexamethylenediamine,p-phenylenediamine, 4- methyl-m-phenylenediamine, bis(paminomethyl)methane, 1,4-diaminocyclohexane, piperazine, and trans-2,5-dimethylpiperazine, may be used. The corresponding diisocyanates, suchas hexamethylene diisocyanate and 4-rnethyl-m-phenylene diisocyanate,may be used as core- -actants whenever available. When low melting lowmolecular weight polymers are desired, it is preferable to preparecopolymers from aliphatic diamines or diisocyanates, with long chain orbranched chain aliphatic diamines producing lower melting polymers morereadily.

Polyamides are prepared by reacting acids or their amide-fanningderivatives, particularly the acid halides, such as those derived :fromoxalic, sucoinic, adipic, suberic, azelaic, sebacic, isophthalic,terephthalic, hexahydroterephthalic, 1,5-naphthalene disulfonic,.1,2-ethanedisulfonic, and 1,6-hexanedisulfonic acids, with the diamineslisted in the two preceding paragraphs. Once again, if it is desiredthat the low molecular weight macrointerrnediate be low melting, it ispreferred that all of the intermediates used to prepare the polyamidesbe aliphatic. Disecondary diamines, such asN,N-diisobutylhexamethylenediamine, are particularly useful for thispurpose.

The polyfunctional essentially monomericorganic polymer intermediate maybe any polymer-forming molecule corresponding to the formulae wherein nis a small integer greater than 1, X is hydrogen more active thanalcoholic hydrogen, Y is a group capable of reacting with alcohol atroom temperature to to form an ester, Z is an organic radical and m is.a small number at least 1. Among such materials may be mentionedalkylene diamines such as ethylene diamine, propylene diamine,,hexamethylene diarnine, as well as phenylene diamine,diaminocyclohexane, diethylene triamine, adipyl chloride, sebacylchloride, terephthaloyl chloride, phenols such as resorcinol, the hischloroformates of the alkylene glycols and the like.

The shaped bodies of the present invention are of continuous and uniformcross-section, i.e. they are solid without soft or open centers. Ingeneral, these structures are relatively stable to hydrolysis under theconditions .used for commercial laundering. This is an importantattribute for filaments which are to be utilized in fabrics subject towashing. Most are more resistant to oxidation than are the conventionalelastic filaments. If desired, their stability can be improved byincorporating commercially available antioxidantsand ultra-violet lightstabilizers.

The high tenacity, high initial modulus, excellent abrasion resistance,and easily controlled elongation of the elastic structures prepared bythe process of this invention 'fit them for many applications,particularly in film and filament form, for which rubber is undesirable.A particular advantage is that uncovered low denier multifilaments canbe used to prep-are sheer elastic fabrics. An important additionaladvantage, particularly for filaments, is that solid structures areobtained by a simple process. A large percentage of the rubber threadsused and are prepared by slitting rubber sheets. This producesrelatively large denier filaments, which cannot be converted readilyinto mnltifil-amentsand are not acceptable for many uses, particularlyin certain fabrics.

In general, the process of this invention provides a very useful toolfor preparing films and fibers comprising high molecular weightcondensation polymers. The process circumvents many of the normal stepsrequired for converting polymeric materials into useful shaped articles.-It provides. the only method for the preparation of shaped articlesfrom certain polymeric materials, for example, those prepared fromintermediates that are unstable at the high temperatures normallyrequired in the condensation reaction. --It provides a method forpreparing elastic polymers of sufliciently high molecular weight at roomtemperatures that the shaped articles are useful. Also, intermediateswhich would normally be too impure-forconventional meltpolymerizationcan be used. In addition, there is. no needto maintain a delicatebalance of-materials in. orderto obtainhigh molecular weight polymer, isrequired by melt polymerization. Flhere 8 is also provided a new methodfor preparing films and filaments comprising certain cross-linkedpolymers.

Many equivalent modifications will be apparent to those skilled in the;art "from a reading of the above description without a. departure fromthe inventive ,con-

,cept.

wherein and and R is a member of the class consisting ,of hydrogen,lower alkyl, and the lower alkylene chainof a heterocyclic diamine andhaving a molecular weight within the range of from about 400 to about7000, and at least one of the other of the said complementary reactivepolymer intermediates being a polyfunctional, monomeric, organicmolecule, the proportionate molecular weights of .macromolecularintermediate to the monomeric molecular intermediate being such that atleast about 30% by weight of the final shaped structure is contributedby the macromolecular intermediate [while at least about 10% by weightofthe final shaped structure is contributed by the monomeric molecularintermediate], the combination of the said complementary intermediatesbeing accomplished by extruding through an orifice on said complementarypolymer intermediate into the other.

2. The process of claim 1 wherein the macromolecular intermediatecomprises at least about 60% by weight of the final shaped article.

3. The process of claim 1 wherein the extruded liquid contains amacromolecular intermediate.

4. The process of claim 1 wherein the macromolecular intermediate isessentially a polyamide.

5. The process of claim 1 wherein the macromolecular intermediate isessentially a polyurethane.

6. The process of claim 1 wherein the macromolecular intermediate isessentially a polyurea.

7. The process of claim 1 wherein the active hydrogens more active thanalcoholic hydrogen are supplied by a mercaptan radical.

8. The process of claim 1 wherein the active :hydrogens more active thanalcoholic hydrogen are supplied by a phenolic hydroxyl radical.

9. The process of claim 1 wherein the active hydrogens more active thanalcoholic hydrogen are supplied by an amino-Nl-IR radical wherein R is amember ,0f the class consisting of hydrogen and alkyl.

10. The process of claim 1 wherein the active hydrogens more active thanalcoholic hydrogen are supplied by an amidino radical.

11. The process of claim 1 wherein the reactive groups capable ofreacting with alcohol at room temperature to form an ester are acidhalide.

12. The process of claim 1 wherein the reactive groups capable ofreacting with alcohol at room temperature to form an ester are carbonylhalide.

13. The process of claim 1 wherein the reactive groups capable ofreacting with alcohol at room temperature to form an ester arehaloformate.

-14. The process of claim 1 wherein the reactive groups capable ofreacting with alcohol at room temperature to form an ester areisocyanate.

15. The process of claim 1 wherein the complementary reactiveintermediates combine to form an amide.

References Cited in the file of this patent or the original patentUNITED STATES PATENTS Magat May 17, 1955

